The present invention relates to a rotor of a rotary electrical machine such as a charging generator intended for vehicular use. More particularly, the invention relates to an improvement in the way in which cooling blades, making up a rotor, are fixed to the rotor.
In a rotor of a charging generator for vehicles, cooling blades are provided for radiating heat produced in the field coil of the generator and for thereby cooling the rotor. FIG. 1 shows a conventional rotor provided with cooling blades. In FIG. 1, a rotor 1 is constituted by a rotary shaft 2, a pair of claw-shaped poles 3a and 3b, a field coil 4, a slip ring 5, and cooling blades 6a and 6b. The field coil 4 is disposed around the rotary shaft 2 and the pair of claw-shaped poles 3a and 3b are arranged such that they can axially sandwich the field coil 4 therebetween. The slip ring 5 is fitted on the rotary shaft 2 at the side end portion thereof. The cooling blades 6a and 6b are fixedly attached to the respective ones of the claw-shaped poles 3a and 3b at a plurality of points 6c at their outer side surfaces by resistance welding.
In the thus-arranged conventional rotor, the positions of the blades 6a and 6b with respect to the shaft 2 is not closely controlled, and therefore sometimes the blades 6a and 6b may be eccentrically fixed to the shaft 2, resulting in an unbalance or the like during rotation. In this case, there is some risk that the blades will fly off the rotor due to breaking of the resistance welds. For this reason, it is necessary to very carefully inspect all welding points during manufacture, and thus there is a disadvantage that the manufacturing efficiency of the rotor is low.